1. Field of the Invention
The present invention relates to an IC card, an information processing device, a communication type identification method, and a program.
2. Description of the Related Art
In recent years, mobile telephones and mobile information terminals equipped with a non-contact type integrated circuit (IC) card or a non-contact type IC chip, and communication devices and information processing devices equipped with a reader/writer function to perform non-contact communication with a non-contact IC card have come into widespread use. Hereinafter, these devices and instruments are also referred to as non-contact communication devices. A read/write unit (reader/writer) and a non-contact IC card can communicate with each other through close proximity communication by using a carrier wave with a specific frequency (for example, 13.56 MHz). For example, when a reader/writer transmits a command that causes a non-contact IC card to execute a predetermined processing, the non-contact IC card executes processing corresponding to the received command, and sends back the execution result as a response signal.
At this time, the reader/writer and the non-contact IC card can transmit a signal using a modulation technology called load modulation, which applies modulation to a carrier wave by changing a load of an antenna according to transmitted data. Normally, this signal is transmitted using an amplitude modulation method called amplitude shift keying (ASK). Further, this signal is transmitted based on a communication type that the reader/writer and the non-contact IC card can use to communicate with each other. For example, this signal is encoded by an encoding format defined by a predetermined communication type, then modulated with a modulation depth defined by the predetermined communication type, and is transmitted.
In this context, recently, attention has been focused on a technology related to a non-contact IC card compatible with a plurality of communication types. Particularly, there is a strong demand for development of a non-contact IC card that can identify, based on a signal received from a reader/writer when establishing communication, a communication type corresponding to the reader/writer accurately and at high speed.
As related technology, for example, a technology for establishing a communication type between a non-contact IC card and a reader/writer is described in Japanese Patent Application Publication No. JP-A-2003-233787. The key feature of this technology is that, when a modulation signal is received from a non-contact IC card or a reader/writer, a plurality of combinations of modulation types and encoding types are sequentially switched to search for a combination that matches the modulation signal.
As another example, a technology related to a non-contact IC card is described in Japanese Patent Application Publication No. JP-A-2005-94760. This technology concerns a technology that identifies a communication protocol of a received signal received from a reader/writer. More particularly, this technology assumes the use of communication protocols called International Standard ISO14443 type A and type B (hereinafter referred to as ISO14443-A, ISO14443-B). The key feature of this technology is that the communication protocol is identified based on header information of the received signal.
As yet another example, a technology related to a non-contact IC card is described in Japanese Patent Application Publication No. JP-A-2006-60363. This technology concerns a technology that identifies a communication type of a received signal received from a reader/writer when establishing communication with the reader/writer. More particularly, this technology assumes the use of ISO14443-A and ISO14443-B, or the IC card standard for high speed processing defined by Japan IC Card System Application Council (JICSAP). The key feature of this technology is that the communication protocol is identified based on header information of the received signal.